Electronic money which is circulated in a manner similar to cash is being put into practical use. The electronic money is accumulated in an IC card. As electronic money, there are a prepaid type and an on-credit type. Further, a method whereby the user inputs money into an IC card from his own account of a financial institution or inputs an unused money amount into his account by using the Internet and a personal computer has also been proposed. A method whereby an electronic use right such as charge for a telephone call, a boarding ticket, or the like is realized by an IC card, particularly, a contactless IC card has also been tried.
According to the electronic money and the electronic use right, since information is accumulated into the IC card, there is an advantage such that falsification is more difficult as compared with that of an existing card of the magnetic stripe type. As countermeasures for security, a method whereby data which is transmitted and received between a reader/writer and the IC card is encrypted is considered.
However, even if the data which is transmitted and received between the reader/writer and the IC card has been encrypted, the security for the electronic money and electronic use right is not always sufficient. A method whereby the electronic money and electronic use right are used as a consideration for the use of digital contents such as distributed music or the like is considered. The security for the electronic money and electronic use right with respect to the digital contents themselves is not higher as compared with that in the case where a process such as powerful encryption, copy protection, or the like has been performed. A fact that there are not cooperative works of the use of the digital contents and the electronic money and electronic use right also becomes a cause of a weak security. Unlike the electronic money and electronic use right, when the digital contents is once circulated, its unitary management is difficult and, if the encryption performed to the contents is decrypted, a necessity of executing another encrypting process again or the like is caused. Therefore, it is much troublesome to change a system.
In consideration of the drawbacks as mentioned above, therefore, it is an object of the invention to provide an electronic money, an electronic use right, a charging system, an information processing apparatus, and reproducing method and reproduction control method of contents data, in which a security can be further improved.